Treatment of hydrocarbons



oct. 13, 1942.

K. M. WATSON :sT/u.

TREATMENT OF HYDROGARBONS- 'Filed May 25, 1940 2 shets-sheet 1 A TORNEYOct 13, 1942 K. MfwATsoN ETAL TREATMENT OF HYDROCARBONS 2 Sheets-Sheet 2Filed May 25, 1940 l |NvEN`ToRs KENNETH M. wATsoN ROBERT l.. SMITHPatented Oct. 13, 1942 i TREATMENT 0F HYDRocAaBoNs Kenneth M. Watson unaRobert' L. smith', chicago, Ill., assignors to Universal Oil ProductsCompany, Chicago, Ill., a corporation of Dela- Ware Application May 25,1940, Serial Nof 337,168 3 claims. `(C41. 2572-242) This inventionrelates to a. process for accomplishing catalytic endothermichydrocarbon conversion reactions under substantially adiabaticconditions and to the method for-regenerating the Acatalytic material insitu without using extraneous cooling means vto remove jthe exothermicheat of reactivation but on the other hand removing such heat assensible heat in thelreactlvating gases.

In the catalytic conversion of hydrocarbons wherein the reaction isendothermic (requiring heat), such as, for example, catalytic cracking,

dehydrogenation, and aromatization, the practice has been'to supply heatto the zene during the period in which the hydrocarbons are in contact`with the catalyst mass in order to maintain the desired conversiontemperature l and to employ some form of extraneous coolingl during theperiod in which the catalytic material is undergoing reactivation so asto 'quickly remove the exothermic heat of reactivation and thus avoidoverheating ofy the catalytic material. One of the more common methodsfor accomplishing this may involve the use of a reactor containing aplurality of relatvely small diameter tubes containing the catalyticmaterial, the tubes being surrounded with a l suitable uid medium forthe purpose of supplying heat to the endothermic reaction or removingheat during the exothermic reaction. Another type of reaction vesselwhich has been employed in accomplishing the reactions above describedis that which contains a plurality of tubular elements surrounded -bycatalytic material and means for introducing a uid cooling or heatingmedium tothe tubular elements for the purpose i' of abstracting heatfrom the surrounding hydrofarbons and catalytic material or for thepurpose- In reactors of the type presently employed, due lo the factthat they contain relatively deep beds of catalytic material, thepressure drop is ordivnarily high necessitating the use ofhighinletpressureswhich is not'always desirable. This is particularlytrue where the catalytic material is.

contained in the small diameter tubular elements for, in most cases, inorder to economically obtain the desired capacity and at the same timeemploy space velocities, (i. e., the unit volume of hydrocarbons broughtin contact with a unit volume of catalyst per unit of time), withinthe-desired range, relatively long tubular elements are employed. Insuch cases, during regeneration of the catalytic material, even thoughexternal cooling is employed, temperatures during the-regeneration mayexceed the maximum allowable temperature to Vwhich the catalyst may besubjected ,and

thereby damage the catalyst to such an extent that its activity ismaterially decreased duringV the subsequent processing periods.

One common diiculty encountered in all re` l actors containingrelatively'deep beds of catalytic material is powdering of the catalystdue to the relatively heavy load which it supports resulting Vin*channeling` of the hydrocarbons through the bed of catalytic materialand greater deposition of carbonaceous materials in some parts of thebed of catalytic material than in other parts of the bed.' Relativelydeep beds, in many cases, are

also objectionable fromthe standpoint of obtaining uniformity ofoperation in systems employing two reaction zones, for example, becausein such cases it is usually vvery diicult to balance the process andreactivating periods, the latter usually requiring more time forcomplete reactivation than the desired length of the process period.

In view of the above vWe employ in our process relatively shallow bedsof catalytic material and to accomplish the objects of the invention,one or more reactors may be employed containing vone or more beds ofcatalytic material. One reactor may, for example, contain a plurality ofbeds of catalytic material through which the hydrocarbons' orreactivating gases pass in parallel ow or it may be operated so thatonly the reactivating gases. pass through the beds of catalytic materialin parallel ow while the hydrocarbons pass through'the various beds in.series. of separate reactors containing individual beds of catalytic'material may also be employed, through which the hydrocarbons orreactivating gases pass in parallel Aflow or, when desired, in series owor, on the other hand, series ow during the hydrocarbon conversionreaction and parallel flow while reactivating thecatalytic material.

shallow beds of catalytic material in each of the reactors,the-reactivation time may be decreased to some extent over thatordinarily required .in

4 reactivating deep beds, because, ,due to the decreased pressure dropof the gases passing through the beds, larger. volumes with a greaterheat capacity may be employed, thus minimizing the danger of overheatingthe catalyticlmaterial when more rapid burning is done. This is on thebasis of substantially complete reactivation -of the catalyticparticles, however, in cases where only the carbonaceous deposit isremoved v from the surface of the catalyst particles the reactivationYtime may bereduced to-a still lower gure l A plurality When employingparallel operated relatively' In one embodiment the invention comprises.

introducing the hydrocarbons to be converted to a catalytic reactorcontaining a plurality of relatively shallow beds of fresh or freshlyregenerated catalytic material, passing said hydrocarbons through saidbeds of catalytic material in series whereby to accomplish the desiredreaction and simultaneously therewith supplying regenerating gases toanother reactor containing a plurality of relatively shallow beds ofcatalytic material, passing said regenerating gases through the rst bedof catalytic material and 4thereafter withdrawing a portion of saidregenerating gases and restoring the 'remaining portion thereof to itsoriginal volume'by introducing cooler regenerating gases from an outsidesource, passing the resulting cooled regenerating gases through the nextsuccessive bed of catalytic material and thereafter withdrawing aportion and replacing this portion with a coolerportion of regeneratinggases introduced from an exterior source, thereafter after eachsuccessive pass of the regenerating gases through the beds of catalyticmaterial withdrawing a portion and adding a cooler portion to restorethe gases to their original volume until the regenerating gases havebeen passed through each successive bed and alteres'sing andregeneration.-

In another embodiment the invention comprises passing parallel streamsof hydrocarbons to be converted through a group of reactors containingcatalytic material capable of promoting the desired reaction,simultaneously therewith passing parallel streams of regenerating gases-containing a controlled amount of oxygen a plurality of reactorswherein each reactor contains only a single bed of catalytic material.

Figs. 3 and 3A are details of the -way valves diagrammatlcally indicatedin Figs. 1 and 2, while Figs. 4, 4A, 5, and 5A are details of the 3-Wayvalves diagrammatically indicated in Fig. 2; Figs. 3, 4 and 5 showingthe valves in one position and Figs. 3A, 4A, and 5A showing thepassageways therethrough shifted.

Referring nowV to Fig. l, the apparatus as shown consists only of tworeactors Aand B but a greater or lesser number may be employed, whendesired to accomplish the objects of the invention. These reactors arepreferably divided into a plurality of compartments i, each compartmentbeing separated 'from the next succes- ,nately operating each of saidreactors in proc- The invention also provides for operating the variouscompartments in parallel by employing a solid partition plate 2. Thismanner of operation, however, will be described more fully later.

In order to make the operation continuous, one v or more of the reactorsis employed as the con version zone at all times while the catalyticmaterial in the other or others is undergoing reactivation. For thepurpose of illustration, therefore, assume that reactor A is on processand the catalytic material in reactor B is undergoing reactivation.

Switching of the stream of reactants and reactivating gases isaccomplished by means of inlet valves VI and V3 and switching of theconversion products and spent reactivating gases is accomplished bymeans of valves V2 and V4. Any suitable valve arrangement capable ofswitching the direction of the iiow of the reactants and 'reactivatinggases may be employed within the scope of the invention. However, forthe sake of simplifying the description and illustrating the processwithout unnecessary complications, each of the switching valves employedis illustrated as either a 4way valve or a 3-way valve, the passagewaysof whichmay be shifted from the positions illustrated in Figs.`3, 4, and5 to the positions illustrated in Figs. 3A, 4A, and 5A. In thedescription which follows, with reactor A on process and thecatalyticmaterial in reactor B undergoing reactivation, valves Vl, V2, and V3 areeach adjusted to the position illustrat-ed in Fig. 3A while valve V4 isadjusted to the position illustrated in Fig. 3.

With the valves. adjusted to the positions described above, thereactants heated to the desired conversion temperature are introduced tothe system through line 5 by means of which they are directed to valveVI. The reactants pass through valve Vi into line 6 by means of whichthey are introduced to reactor A. The reactants pass through thesuccessive beds of catalytic masive compartment by means of partitionplates terial in reactor A-and while in contact therewith the desiredreaction is effected. Reaction products are discharged from reactor Athrough line 1 by means of which they ane directed to valve V2wherethrough they pass into line 8 by means of which they may beconducted to separation and collection equipment or to any desirediurther treatment. No external heat is supplied to reactor A during theconversion treatment, the reaction being accomplished undersubstantially adiabatic conditions utilizing sensible heat in the vreactants as the heat of conversion.

material in reactor B may be reactivated by contacting therewith asuitable inert gas, such `as combustion gases containing controlledamounts of air or oxygen. Reactivating gases with the desired oxygencontent and at the desired reactivating gas temperature are supplied tovalve VI in the manner to be described later, wherethrough they passinto line 8 by means of which they are supplied to the iirst compartmentin reactor B. When the oxygen-containing reactivating gases are broughtin contact with the catalytic material the carbonaceous substancesdeposited thereon during the previous processing period are burned andremoved as combustion gases. The partially spent combustion gasesleaving the rst compartment containing at least some of the heatof'reactivation as sensible heat are collectedin compartment 4 wherefromregulated portions are Withdrawn through lines I0 undergoingreactivation, in order to prevent difand II to valve V4, wherethroughthey` passinto line l2 subsequently combining with other spentreactivating gases removed in the manner to be described later. Coolreactivating gases supplied' to valve V3 in the manner to be describedlater pass therethrough into line I3 and thence into line I4 by meanslof which they arevintroduced to the upper portion of the next successivecompartment wherein they are commingled with the other' portion of thepartially spent reactivating gases supplied -to this comparment from thepreceding comparment through perforated plate 2. Cooled reactivatinggases are introduced to each successive compartment in the manner abovedescribed, while at least part of the spent'reactivating gases arewithdrawn after each pass of the reactivating gases through thecatalytic material in the various compartments, coolerreactivating gasesbeing introduced to each successive compartment in the manner abovedescribed to cool the gases leaving the preceding compartment.

vSpent reactivating gases are withdrawn from reactor B by way of line I5by means of which they are supplied to valve V2 wherethrough they passinto line I6, commingling therein with the other spent reactivatinggases withdrawn in the manner above described and supplied to line I6 byway of line I2.

The spent reactivating gases may-*be recycled to the system in thefollowing manner: A portion or all of the spent gases in line I6 may bewith- 4 drawn from the system by way of'line I1 and valve I8 andpreferably a portion corresponding to the excess in the system resultingfrom the combustion of the carbonaceous materials in reactor B and dueto the introduction of impurities, such as nitrogen, withthe oxygenintroduced, which will be described later. The remaining portion of thespent reactivating gases in line I3 may be directed through valve I9 tocompressor f v2li. Compressor 20 discharges through line 2i with anoxygen-containing gas in the manner to be described, and the mixturesupplied 'to'valve VI for use as above described. When desired,

and particularly at the start ofthe operation,

fresh reactivating gases may be supplied to the systemfby way of line2S, valve 21, and line 24.

The remaining portion of the reactivating gases in line 2l is directingvthrough line 28 and valve 23 into heat exchanger 30 where it is pref--erably c ooled by indirect heat exchange with a suitable cooling mediumintroduced to heat exchanger by well known means. The cooledreactivating gases leaving heat exchanger 30 are directed through line3| vand valve 32 to-valve V3 for use-as above described. -Air or oxygenfor use in reactivation may be introduced by way o! line 33 and valve 34into line 35. A portion thereof may be directed through valve 36 intoline 24 for use as above describedand the remaining portion. thereofmay-be directed through valve 31 into line 3| wherein it commingles withthe cooled reactivating gases in line 3I for use in reactivating asabove described.

While the catalytic material in reactor B is fusion of the reactantsthrough or condensation .in the various lines and valves leading fromintermediate points in reactor A, a suitable inert gas, such vas steam,hydrogen, orsome hydrocarbon gas, may be introduced through line 38 andYvalve 39 to line 40. Valve 4I being closed, the gas introduced toline,4II is directed through valve V3 into line 42 and thence into line43 by means of which it is introduced in relatively small quantities tothe various compartments. Similarly, and for the same purpose, an inertga`s may be introduced through line 44 and valve 45 to line 46. Valve 41being closed, the inert gas in line 46 is directed through valve V4 intoI line 48 and thence into line 49 by means of which it is-supplied tocompartments 4 for the above mentioned purpose.

When the catalytic material in reactor-A approaches the state of reducedactivity, at which time it is advantageous to apply freshly regen-4erated catalyst for the treatment of the reactants, the supply of air tothe reactivating gas stream is momentarily discontinued so that reactorB is purged of oxygen-containing gases.

After the purging in reactor B is comzleted, valves VI, V2, and V3 areswitched to` the vposition illustrated in Eig. 3 and valve V4 isswitched to the position illustrated in Fig. 3A, at which timeoxygen-containing gases are introduced to reactor A and the reactants toreactor B. When desired suitableprovisions may be made for preventingcontamination between the various streams by the proper regulation ofthe switching valves. Means for 'accomplishing this, however, are 'wellknown and are therefore not illustrated. v

After all the valves have been adjusted to their new positions, the flowof reactants in line I will be throughvalve VI into line 9 by means ofwhich it is supplied to reactor B, passing therethrough in contact withthe mass of catalytic material in order to effectthe desired reaction.

Conversion products from reactor B are withdrawn by way of linev I5 anddirected through valve V2 into line 8, the productsv thereafter beingsubjected to any desired further treatment; During the process period inreactor B, the inert gas in `line 40 introduced as above described isdirected through valve V3 into line I3 and thence through line I4 intothe various compartments in reactor B to prevent loss of valuablehydrocarbons by diiusion through these lines. Simultaneously therewith,the inert gas introduced to line 46 as previously described is directedthrough valve V4 into line II and thence through line III intocompartments 4 for the purpose of preventing loss of valuablehydrocarbons by condensation in the various lines.

While reactor B is on process, reactivating A gases in line 24 aredirected through valve VI into line 6 by means of which they are intro--duced to reactor A. Reactivating gases after .passing through the rstbed of catalytic materialV in reactor A are cooled. by withdrawing aportion thereof through line 49 after-which it is directed through line48 to valve V4 and thence through line I2 into line I6 for treatment asvY above described. A portion of the reactivating gases withdrawn isreplaced by a cooler portion introduced by way of line 3|, valve V3,lines 42 and 43 and t'nese cooler reactivating gases contacted with thenext successive bed 0f catalytic material. The treatment above describedis fol-- lowed after thereactivating gaseshave passed r through eachsuccessive bed of catalytic'mate-- rial, the ow of reactivating gases toreactor A being continuous until the' catalytic material containedtherein is substantially completely reactivated. The reactivating gasesleaving the last bed of, catalytic material in reactor A are V3 are eachadjusted to the position illustrated v in Fig. 3A'while valve V4 isadjusted to the position illustrated in Fig. 3. In` this case, thereactants will be supplied in the desired proportionA A to valve VI byway of line 5 and to valve V3 by way of line 5, line 40, and valve 4I.The reactants supplied to valve VI pass therethrough into line 6 bymeans of which they are introduced to the rst compartment in reactor A.Simultaneously therewith, reactants supplied to valve V3 passtherethrough into line 42 and thence into line 43 by means oi which theyare introduced .to the various other compartments in reactor A.Conversion products from the various compartments in reactor A arewithdrawn by way of respective lines 'l and49. Those in line are thendirected through line 48 to valve V4 wherethrough they pass into line48' and thence through valve 41 intov line 8, while the conversionproducts in line 'l pass through valve V2 into line l, comminglingtherein with the other conversion products supplied to this line by wayo! line 4S as above described. l

Reactivating gases are supplied to .the individual compartments inreactor B by way of line 24, valve VI, and line 9. and by way o!v line3|, valve V3, and'lines i3 and I4.' Spent reactivating gases arewithdrawn from the separate compartments by way of respective lines Iland I5, those in line I0 being directed through line II and thencethrough valve V4 into line I2 by means of which they are supplied toline I6.'

and those in line I5 being directed through valve V2 into line I6,commingling therein with the other spent reactivating gases supplied tothis line as above described, the treatment of reactivating gases fromthis point on being substantially as above described. I

When the catalytic material in reactor A approaches the state o! reducedactivity, whereupon it becomes desirable to employ fresh or freshlyregenerated catalysts, switching valves may be adjusted to the positionsnecessary to provide for introducing reactivating gases to reactor A andreactants to reactor B. Further description in this connection isunnecessary, the flow from this point on being' obvious to any skilledin the art In another manner of operating the process of the invention,wemay employfor example,

' a plurality of reactors each containing asingle bed of catalyticmaterial. The reactors are preferably grouped. such as illustrated inFig.

"2L so that while` one-group of reactors is on process the catalyticmaterial in another group `ma y; be undergoing reactivation.v In Fig. 2each group is shown as consisting of three reactors,

however, a greater or lesser number may be employed, when desired. Inthe illustration shown in Fig. 2, the reactants may be divided into aplurality' of parallel streams corresponding to the number of reactorsin the group on process and each stream is supplied to a separatereactor or, when desired,`a stream vof reactants maybe passed throughthe various reactors in each group in series. Provisions are also madefor supplying reactivating gases to the group of reactors containing thecatalytic material undergoing reactivation in the same manner, i. e.,the

'reactivating lgases may be divided into a plurality of parallel streamswhich are separately inl plied to the various reactors in parallelstreams.

Assuming then that reactors C, D, and E are on process and the catalyticmaterial in reactors F, G, and H is undergoing reactivation, valve V5 isadjusted to the position illustrated in Fig. 3A while valve V6 visadjusted to the position illustrated in Fig: 3. Valves V'I, VB,v VIS,and VI4 are each adjusted to vthe position illustrated in Fig. 4 whilevalves V9, VIo, VII, and VI2 are gch adjusted to the positionillustrated in Fig.

Reactants supplied by'way of line Sl are directed through valve V5 intoline 5I by means of which they are introduced to reactor C. passingtherethrough in contact with the catalytic material contained therein.'Theproducts from reactor C are directed through line 52 and valve V8into line I3 and thence through valve V1 into line I4 by means of whichthey are introl -lection and separation equipment or subjected to anydesired further treatment.

The oxygen-containing reactivating. gases in line 6I are directedthrough valvefVS infn line 62 wherein the reactivating gases are.divided into three parallel streams and the mst supplied to .reactor Fby' way oi.' line 63, valve VI I, and

line 64 and the second stream supplied to reactor G by way of line G5,valve VI2, and line 66 and the third stream supplied to reactor H by wayof line 62. Spent reactivating gases arewithdrawn from reactor H by wayof line 61. pass through` valve VI4 into line 68, and combine thereinwith spent reactivating gases withdrawn from reactor G by way of line69. valve VH. and.

line 10 and with spent'rea'ctivating gases withdrawn from reactor F byway of line 1l. The

.mixture of spent reactivating gases in line 68 are thereafter directedthrough valve V6 into line 12 and discharged from the process or may be4recycled in themanner described in connection L with F18'. 1.

When the catalytic material inl reactorsV C, D,

' and lilv approaches the state of reduced activity whereupon itbecomes, desirable to employ fresh or freshly regenerated catalysts,`the stream ofreactants and reactivating gases may be switched, gwhereupon the reactants are supplied to reactors F, G, and H and thestream of reactivating gases to the reactors C, D, and E. Switching ofthe streams may be accomplished by adjustingy the position of valve V tothat illustrated in Fig. 3V

and valve V6 to the position illustrated in Fig. 3A. vIn addition,valves V1, VB, VI3, .and VII are each adiusted tothe positionillustrated in Fig, 4A while valves V9, VIII, VII, and VIZ are eachadjusted to the position illustrated in Fig- 5- In this case, .the flowof reactants will be through valve V5 into line 62, thence through-reactor H into line 61, through valve VII-into line 14, through reactorVIZ into line 86, thence through reactor G into 1ine69, through valveVII into line 13, through valve VII into line 64, thence through reactorF into line 1 I, after which they may be conducted through line 6 8 toValve volume and temperatureV by the introduction of y jected toreactivation in the presence oifcombustion gases containing aproximately 2% oxygen the mixture having bee preheated to a temperatureof approximately 900 F.l A portion of the spent reactivating gases andcombustion products leaving the ilrst bed oi catalytic material iswithdrawn from the system and the reactivating gas volume is readjustedto its original cooler combustion gases and air formed in the -manner tobe described later. The spent re- VB wher'ethrough they pass into line80.. 'I'he stream of reactivatlng gases passes through valve V 5 intoline 5I and thence in parallel through reactors C, D, and E, one streambeing introduced through reactor C by way of line v5I, another streamthrough reactor D by way of line 15, valve V1, and line 5l, and anotherstream to reactor E by way of line 16, valve V8, and line 51. Spentreactivating gases are withdrawn from reactor C by way of line 52 and`are directed through valve V9 into line 59, commingling therein withspent ample, operating the group. of reactors to which the reactivatinggases are supplied in series', while the group to which the reactantsare supplied is operated in parallel, and since all these modicationsare apparent by mere -reference to the drawings, any further descriptionis unnecessary.

An example of one specific. operation of the process as it may beaccomplished in an apparatus such as illustrate'dand above' described isapproximately as follows: The charging' stock comprising a 36 A. P, I.gravity Mid-Continent gas oil is heated and vaporized at a temperatureof 950 F. and at a superatmospheric pressure o! 40 pounds per squareinch. 'I'he heated reactants are introduced to a reactor containingthree beds oi' catalytic material, the reactants lpass through eachsuccessive bed in series. The conversion products from the reactor arefractionated to separate lgasoline boiling range hydrocarbonscorresponding to approximately 40% by volume of the charging. materialand the gasoline and intermediate conversion produc separatelyrecovered.

Simultaneously therewith the catalytic material' contained in anotherreactor likewise con- .i taining three beds of catalytic material issubactivating gases and combustion products `leaving each successive bedof catalytic materialare treated in the-manner above described, i. e., aportion is withdrawn andthe 'residual portion thereof readjusted to theoriginal'volume, and

temperature. Spent reactivating gases and combustion products leaving`the last bed'oi catalytic material are commingled with the other spentreactivating gases and combustion products removed as above described.-and a portion corresponding in volume to the combustion products -formedin reactivating the catalyst is removed and discharged `from the systemwhile the re- V maining portion thereof is separated into two furtherportions, one of which is cooled to the desired reactivatingtemperature, after which air is added to increase its oxygenconcentration to approximately 2% and the mixture thereafter supplied tothe ilrst bed of catalytic material.

The other Afurther-portion is cooled` to a temperlature below thereactivating gas temperature and sulcient air added to this portion sothat upon introduction of this mixture in the inter- `mediate pointsinthe reactor, as above described,

the oxygen' concentration .in the reactivating gases entering the nextsuccessive bed of catalytic material is of the desired value and at thedesired temperature. l

We claim as our invention:

1. In a process employing a relatively large mass ot catalyst whichbecomes carbonized upon use wherein said mass is divided into aseries ofrelatively small beds, the method o! regenerating the carbonizedcatalyst mass while maintaining a substantially uniform regeneratingtemperature which comprises passing a stream of oxygen' containing gasin series through. said beds to burn carbonaceous matter therefrom,removing a portion of the gases from said stream between successive bedsand adding relatively eco'. oxygen-containing gas to the stream betweenthe successive beds to adjust the temperature .and

oxygen concentration thereof. 1

2. AThe method oi' claim l further characterized in, that atleast aportion of the gases removed from the stream of regenerating gases arecooled, the oxygen concentration modiiled and the thus modiiled gasesreturned to the stream of regenerating gases as said cooloxygen-containing gas.

3. The process of 'claim 1 further character-` ited in that said seriesof beds are situate withinV the same reaction zone.

KENNETH M. WATSON. ROBERT L. Sm

